苏北溱潼凹陷戴南组一段次生孔隙形成与分布特征

次生孔隙是戴南组一段（E2d1）砂岩储层的主要孔隙类型，其分布与油气聚集关系密切。本文在沉积、成岩作用研究基础上，探讨了次生孔隙成因机理，指出有机酸的溶解作用是形成戴南组一段次生孔隙的主要原因，并根据有机质成熟生烃和粘土矿物的转变导致的泥岩压实异常特征，进行次生孔隙的横向分布预测，取得了凹陷不同构造带次生孔隙分布与油气聚集规律的新认识。

FORMATION AND DISTRIBUTION OF THE SECONDARY POROSITY IN THE FIRST MEMBER OF THE DAINAN FORMATION IN THE QINTONG DEPRESSION,NORTHERN JIANGSU

The secondary porosity is the major porosity type of sandstones reservoirs in the firstmember of the Dainan Formation in the Qintong depression,northern Jiangsu. The distri-bution of the secondary porosity is closely related to oil and gas accumulation. The authorinquires,on the basis of the studies of diagenesis,into the genetic mechanism of the sec-ondary porosity and owes its origin to the dissolution of organic acids. Some speculationsupon the horizontal distribution of the secondary porosity were also made by the author inthe light of organic maturity and compaction anomaly of the mudstones caused by claymineral transformation,thus resulting in the improvement of the knowledge of the distri-bution of the secondary porosity and oil and gas accumulation in different structural zonesin the study area.